Use a status object for errors so a message can be returned.

Also delay deletion of subfields until the entire message is
deleted.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/upb.c b/src/upb.c
index e82a8e4..e58d272 100644
--- a/src/upb.c
+++ b/src/upb.c
@@ -5,6 +5,7 @@
  *
  */
 
+#include <stdarg.h>
 #include <stddef.h>
 
 #include "upb.h"
@@ -35,3 +36,14 @@ struct upb_type_info upb_type_info[] = {
   TYPE_INFO(BYTES,    UPB_WIRE_TYPE_DELIMITED,   struct upb_string*)
 };
 
+void upb_seterr(struct upb_status *status, enum upb_status_code code,
+                const char *msg, ...)
+{
+  if(upb_ok(status)) {  // The first error is the most interesting.
+    status->code = code;
+    va_list args;
+    va_start(args, msg);
+    vsnprintf(status->msg, UPB_ERRORMSG_MAXLEN, msg, args);
+    va_end(args);
+  }
+}